1. Field of the Invention
The present invention concerns an electrode for a controllable, electrochromic indicator device with an electrochromic layer between a transparent first and a second electrode.
2. Description of the Prior Art
Electrodes of the mentioned type are already known from the publications DT-OS 2,125,337; DT-OS 2,201,104; DT-OS 2,201,139 and DT-OS 2,363,306. Such electrodes exhibit a layer of liquid electrolyte and are so arranged in the electrochromic indicator devices that under the action of an electric field through the liquid electrolyte contacting the electrochromic layer a rapid and uniform change in the absorption characteristic is produced over large areas of the electrochromic material, and, thus, a rapid and uniform indication is made possible. Since such indicator devices are preferably in the form of large-area cells, the sealing of these cells presents considerable difficulties. Leaking of the cells, however, is to be avoided, since the loss of liquid electrolyte not only affects the operation of the indicator devices, but, also, can foul surrounding devices and even destroy them when high proton-content electrolytes like sulfuric acid are used.